Variation in growth performance of Ryukyu-ayu, Plecoglossus altivelis ryukyuensis, inferred from otolith analysis

Murase, Iki; Kawakami, Tatsuya; Iguchi, Kei’ichiro

doi:10.1007/s10228-018-0638-3

Cited by 4 publications

(5 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The concentration ratio of Sr:Ca was analysed using an X‐ray electron probe micro analyser (EPMA; JXA‐8230; JEOL; http://www.jeol.co.jp), as described by Murase et al . (). The Sr:Ca was measured along a line from the otolith core to the posterior edge.…”

Section: Methodsmentioning

confidence: 97%

“…To estimate the standard length ( L S , mm) at catch ( i.e ., L S at maturity) from the size of the head stored in 99% ethanol, we used the following equation by Murase et al . ():

\log_{10} L_{S} = 0.5469 \times \log_{10} L_{sn} + 1.4982

where L Sn is the length between fish's snout and eye.…”

Section: Methodsmentioning

confidence: 99%

“…As with A. japonica , several studies have suggested that P. a. altivelis has a facultative migration pattern in estuaries (Iguchi et al ., ; Tsukamoto, ). Our previous study performing otolith Sr:Ca analysis on 50 Ryukyu‐ayu confirmed this possibility by revealing the intraspecific variation of salinity profiles during the marine period (Murase et al ., ). Although a large individual‐based variation was observed (Murase et al ., ), Ryukyu‐ayu mainly remained in estuaries rather than the sea during the early ontogenetic stage.…”

Section: Introductionmentioning

confidence: 97%

“…Our previous study performing otolith Sr:Ca analysis on 50 Ryukyu‐ayu confirmed this possibility by revealing the intraspecific variation of salinity profiles during the marine period (Murase et al ., ). Although a large individual‐based variation was observed (Murase et al ., ), Ryukyu‐ayu mainly remained in estuaries rather than the sea during the early ontogenetic stage. High temperatures combined with high salinity requires a higher maintenance cost (Iguchi et al ., ) and depresses larval growth (Ito et al ., ; Kishino et al ., ); therefore, estuaries would be a preferable habitat than the sea, especially for larval and juvenile Ryukyu‐ayu in subtropical areas.…”

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Facultative amphidromy involving estuaries in an annual amphidromous fish from a subtropical marginal range

Murase

Iguchi

2019

Journal of Fish Biology

Self Cite

View full text Add to dashboard Cite

Variation in the life cycle of diadromous fishes can be explained by differential food availability between marine and freshwater habitats, since migration is often interpreted as a mechanism for exploiting food resources. Theoretically, a migration pattern of mainly remaining in freshwater occurs in tropical and subtropical habitats where fluvial productivity possibly exceeds marine productivity. However, in Yakugachi River, Amami-Oshima Island, southern Japan, low nutrient concentrations in the river suggest that food availability is limited for the subtropical Ryukyu-ayu Plecoglossus altivelis ryukyuensis. Since Ryukyu-ayu is an amphidromous fish that mainly grows in rivers after spending 2 months in the sea, limited food availability in rivers would force this species to migrate to other habitats with better food availability. Otolith increment and Sr:Ca analyses of 48 adult Ryukyu-ayu collected from the Yakugachi River revealed that all individuals visited estuaries more than three times after moving upstream. Although the specific growth rates of this species in the river had no correlation with the salinity profile in the fluvial period, this movement may be an adaptive choice because the salinity profile significantly affected the body size at maturity. Our results highlighted individual-based variations in amphidromous migration for utilizing estuaries, which could be explained by relatively higher productivity in estuarine than in freshwater and marine habitats. K E Y W O R D S estuary, individual-based migration pattern, otolith Sr:Ca, subtropical amphidromous fish

show abstract

Section: Methodsmentioning

confidence: 97%

“…To estimate the standard length ( L S , mm) at catch ( i.e ., L S at maturity) from the size of the head stored in 99% ethanol, we used the following equation by Murase et al . ():

\log_{10} L_{S} = 0.5469 \times \log_{10} L_{sn} + 1.4982

where L Sn is the length between fish's snout and eye.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 97%

See 2 more Smart Citations

Facultative amphidromy involving estuaries in an annual amphidromous fish from a subtropical marginal range

Murase

Iguchi

2019

Journal of Fish Biology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ryukyu-ayu Plecoglossus altivelis ryukyuensis Nishida, a subspecies of ayu P. a. altivelis Temmink & Schlegel, is an amphidromous fish having an annual life history (Nishida 1988;Shinomiya 1997;Aritomi et al 2017;Murase et al 2018). This species is currently listed in the Japanese Red Data Book as a critically endangered fish found only in Amami-Oshima Island and Okinawa Island in southern Japan (Nishida 1988;Nishida et al 1992;Shinomiya 2003;Tachihara 2015).…”

Section: Introductionmentioning

confidence: 99%

Does construction in the spawning ground improve the riverbed conditions making it suitable for spawning of the Ryukyu-ayu Plecoglossus altivelis ryukyuensis?

et al. 2020

Self Cite

View full text Add to dashboard Cite

Maintaining a certain number of spawning grounds for endangered fish is particularly important in rivers and streams where the environment changes drastically through floods and exploitations. Ryukyu-ayu Plecoglossus altivelis ryukyuensis is an endangered annual fish inhabiting the few streams and rivers flowing through the Amami-Oshima Island, southern Japan, and spawns in the lower reaches at sites with the specific riverbed conditions. In the island, resident volunteers along with researchers modify riverbed manually to provide conditions suitable for the natural spawning of the fish every year. This study investigated the effects of these activities on the riverbed conditions and consequently on the spawning by Ryukyu-ayu in two rivers. Our results showed that riverbed hardness and the amount of silt significantly decreased in the modified areas, but not in the adjacent unmodified areas. In one of the two rivers, the modification suppressed the settlement of net-spinning caddisfly larvae Stenopsyche schmidi that promote consolidation of the riverbed. The riverbed conditions in the modified areas were similar to those in the sites where P. a. ryukyuensis indeed spawned. These results suggest that manual modification is efficient in improving riverbed conditions for the spawning of Ryukyu-ayu.However, the eggs of the fish were not found at the modified areas in both rivers. It will be necessary to develop effective and practical ways of selecting sites for modification without obstructing the natural spawning in this fish.

show abstract

Estuarine dependency of Lates japonicus in Shimanto Estuary, Japan, inferred from otolith Sr:Ca

Gonzalvo

Kawakami

Tanoue

et al. 2021

Estuarine, Coastal and Shelf Science

View full text Add to dashboard Cite

Variation in growth performance of Ryukyu-ayu, Plecoglossus altivelis ryukyuensis, inferred from otolith analysis

Cited by 4 publications

References 17 publications

Facultative amphidromy involving estuaries in an annual amphidromous fish from a subtropical marginal range

Facultative amphidromy involving estuaries in an annual amphidromous fish from a subtropical marginal range

Does construction in the spawning ground improve the riverbed conditions making it suitable for spawning of the Ryukyu-ayu Plecoglossus altivelis ryukyuensis?

Estuarine dependency of Lates japonicus in Shimanto Estuary, Japan, inferred from otolith Sr:Ca

Contact Info

Product

Resources

About